Chuck.



V. J. WAHLSTROM. v

GHUGK.-

APPLICATION IILBI) MAR. 28, 1913.

' Patented 0057,1913;

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ensure a. WAHLSTBOM,--OF naooxtrmnnw Yerm, sssreivon To wAHLsrRoM TOO GOMPAHY, or NEW YORK,- N, Y.. mconronarron or NEW YORK.

CHUCK. v

Tooll whom, it ma concern:

' Be it known t at I, VERNEB J. WAnL- STB'QM, a citizen of the United States, IESIdat Brookl n, county of Kings, and

S ate of New or'k, have invented a new and iiseful Improvement. in Chucks, of

which the following is a specification.

. This inventionrelates to an improvement inehueks of the known type wherein there is employed a spring pressed rotary member' operable b' .han against the action of its spring whi e' the chuck it rotating and having cam surfaces for operating the jaws to clamp a tool shank, and it has for its mainpb'ect the production of a device of this kin provided with tapered jaws for engaging tapered tool shanks and with means for preventing'a tapered tool shank from wedging the jaws against the cam surfaces with a force sufiicient to prevent hand operation of that part of the chuck which controls the movement of the jaws.

A further objedt is the production of simplified clamping jaws having one edge rounded for direct contact with the rotary rnember of the chuck and having its opposite edge shaped to form aneccentr'lc cam surface adapted to firmly grip a tool shank, the gripping action being produced by a rocking movement of the jaw.

With these and other objects not specifi- "cally' mentioned 1n view, the invention consectional view of a device constructed Sin accordance with the invention and 1llustrating the relative positions of the parts when the tapered tool shank is first inserted in the chuck; Fig; 2 is a corresponding view but illustrating the parts in the position they occupy when the tool is under pressure," as forrinstance when driven; Fig. 3 is a broken sectional view taken on the line 3-3 in Fig.

l and Fig. 4 tea view taken on the same line-in Fig. 1 but showing the parts in different positions.

In the deviceaselected to illustrate the" Specification of Letters Patent. application filed March as, 1918. Serial No. 757,433.

Patented Oct. 7, 1913.

vention, there is provided a body 6 having three radial slots 7 cut through its walls and opening into a tapered central aperture 8 adapted to receive a tapered tool shank.

The body is further provided with a shank 9 driven or otherwise fastened therein, for V the purpose of attaching the device to a drill press or other machine tool. The device is further 'rovided with an annular shell 10 surroumli and axially movable thereon. This shell 5 provided with three internal cam surfaces 1, and is held in position by means of two caps 12 and 13 screwed or otherwise fas tened to the shell 10. These caps 12 and 13 are adapted to respectively engage rabbets 14 and 15 formed on the body 6, the rabb'ets .being spaced apart a sufiicient -distance to permit a relative longitudinal movement of the shell and body. A torsion spring 16 is coiled around the body within the shell,

one end being fast to the body and the"other to the shell as is clearly shown in Fig. 1.

For thepurpose of clamping the tool in the central aperture 8 thereis provided a plurality of tapered jaws 17, one of which works in each slot 7. The outer edge of each jaw is rounded and contacts with one of the internal cam surfaces 11 before referred to.- The inner edge of each jaw is shaped to form an eccentric cam surface adapted to firmly grip a tool shank in the central aperture 8 when brought into contact therewith, the gripping action being ng the body, and rotatabl I produced by a rocking movement of the jaw I held against its cooperating cam surface l1 by the action of a spring 18 which engages ,sa'id jaw and is partially housed in a bore 19' formed in the chuck body 6, asciearly shown in Fig. 3. spring is to force the jaw outwardly against The function ofwthis the cam surface 11 and to rock 'the j-aw in a reyerse direction after a tool shank has beenreleased to return said jawto its nor-4 nia'l position, orthat shown in Fig'. 3;

'lhese springs serve to n'ormally hold the jaws in the position'shown in Fig. 3 and when a tool is engaged by the jaws and the jaws are; thereby rocked, 'the"spring is buckled "in its housing, the acre-or which is in the earlier chucks of this type.

' large enough to permit this action. It will be noted that the j aws are somewhat shorter than the slot 7 so that they are free to move therein not only radially but axially, or along the axis of the chuck.

When no tool shank is in the chuck, the parts occupy the positions shown in Fig. 4 and when a tapered tool shank is inserted in the central aperture 8, it contacts with the long operating faces of the jaws. It is to be understood that the tool shank is inserted in the chuck while the latter is rotating in the drill press or other machine tool, and that to open the jaws and permit the insertion of the tool shank, it is necessary only to seize the shell 10 and operate it by hand against the action of the spring 16 as After a tapered tool shank has been inserted in the central aperture and the shell released, the spring then operates the shell to force the jaws inwardly to clamp the tool shank against slippage during the rotation of the chuck. It has been found, however, that tapered jaws and a tapered tool shank cannot be used in chucks of a similar type heretofore known for the reason that when the operating pressure is brought upon the tool for drilling or other work, the tapered shank of the tool wedges the jaws against the cam surfaces with force suiiicient to prevent the hand 0 eration of the shell. It will be readily nn erstood by an inspection of Figs. 1 and 2, that the shell is not only rotatable upon the body of the chuck but is axially movable thereon and that the jaws are not only radially movable in the slots but are also axially movable therein. When pressure is brought upon the drill or other tool in the chuck, the tapered shank of the tool retreats in the aperture, carrying with it the jaws and the shell or rotary member surrounding the body portion of the chuck. This retreating movement continues until the extreme end of the tool shank strikes an abutment 24 carried by the chuck body and located at the inner end of the central aperture. It will be understood by an inspection of Fig. 2 that the end of the tool shank strikes the abutment before the jaws and the outer shell have reached the limit of their axial movement. After the tool shank reaches the abutment, the pressure is transferred to said abutment and the jaws are not subjected to the wcdging action oceuriug in the older chucks.

Changes and variations within the scope of the appended 'claims'm'ay be made in the structure by means of which the invention is carried into effect. The invention there fore is not to be restricted to the precise details of the structure shown and described.

What is claimed is:

1. in a rotating chuck for tapered tool shan s the combination with movable taoperation of said member.

member.

pered jaws, of a spring pressed rotaiymem- {Int a tool shank clamped therein to prevent the tapered shank u'n'der operating pressure from wedging the jaws against the cam surfaces with force sufficient to prevent hand 2. In a rotating chuck for tapered tool shanks, the combination with radially movable tapered jaws, of a spring pressed rotary member operable by hand against the action of its spring while the chuck is r0- tatmg and having cam surfaces for operating the jaws to clamp a tool'shank, and an abutment carried by the chuck for limiting relative axial movement of the chuck and a tool shank clamped therein and restin against theabutinen't to prevent the tapereshank under operating ressure from wedging the aws against the cam surfaces with force su icient to prevent hand operation of said member:

3. In a rotating chuckfor tapered tool shanks, the combination with radially and axially movable tapered jaws, of a spring pressed rotary member operable by han against the action of its spring while the chuck is rotating and having cam surfaces for operating the jaws to clamp a tool shank, and an abutment carried by the chuck for limiting relative axial'movement of the chuck and a tool shank and the jaws clamping the latter to prevent the tapered shank under operating pressure from wedging the jaws against the cam surfaces with orce sufiicient to prevent hand operation of said 4. In a rotating chuck for ta and tool shanks, the combination with a c uck body having radial slots opening into a central aperture, of jaws shbrterthan and radially and axially movable in said slots, aspring pressed rotary member surrounding the chuck body and rotatin and having cam surfaces for 0 erating the jaws to clamp a tool shank, an an abutment at aperture for limiting relative axial movement of the chuck body and a tool shank and the jaws clamping the latter to prevent the tapered shank under operating the inner end of the central operable by hand againstthe action of its spring wh lethe chuck is reverie surrounding the chuck body and operable by hand against the action of its spring while the chuck is rotating1 and having cam surfaces for operating t e jaws to clamp a tool shank, and an abutment at the inner end of the central aperture for limiting relative axial movement of the chuck body and a tool shank and the jaws clamping the latter and the member operatin the jaws to prevent the tapered shank under operating pressure from wed ing the jaws against the cam surfaces with fzarce sufiicient to prevent hand operation of said member.

6. In a rotating chuck for tapered tool shanks, the combination with a spring pressed rotary member operable by hand against the action of its spring while the chuck is rotatin and'having cam surfaces for operating 51?) jaws to clamp a tool shank, of a plurality-of movable tapered jaws one edge of each of which contacts with the cam surfaces and the opposite edge of which is shaped to form an eccentric cam surface for gripping a tool shank by a rocking movement, and means for limiting relative axial movement of the chuck and the tool shank clamped therein to prevent the tapered shank under operating pressure from wedging the jaws against the cam surfaces with force sufficient to prevent hand operation of said member.

7. In a rotating chuck for tapered tool shanks, the combination with a spring pressed rotary member operable by hand against the action-of its spring while the chuck is rotating and having cam surfaces for operating the jaws to clamp a tool shank, of a plurality of radially movable tapered jaws one edge of each of which contacts with the cam surfaces and the opposite edge of which is shaped to form an eccentric cam surface for gripping a tool shank by a rocking movement, and an abutment carried by the chuck for limiting relative axizgl movement of the chuck and a tool shank clamped therein and resting against the abutment to prevent the tapered shank under operating pressure from wedging the jaws against the cam surfaces with force sufficient to prevent hand operation of said member.

8. In a rotating chuck for tapered tool shanks, the combination with a spring pressed rotary membcr operable by hand against the action of its spring while the chuck is'rotating and having cam surfaces for operating the j aws to clamp a tool shank,

of a plurality of radially'and axially inov-,

able tapered jaws one edge of each of which contacts with the cam surfaces and the opposite edge of which is shaped to form an eccentric cam surface for gripping a tool shank by a rocking movement, and an abutment carried by the chuck for limiting relative axial movement of the chuck and a tool shank and the jaws clamping the latter to prevent the tapered shank under operating pressure from wedging the jaws against the cam surfaces with force suflicient to prevent hand operation of said member.

9. In a rotating chuck for ta ered tool shanks, the combination with a c uck body having radial slots opening into a central aperture, of a spring pressed rotary member surrounding the chuck body and operable by hand against the action of its spring while the chuck is rotating and having cam surfaces for operating the jaws to clam a tool shank, a plurality of jaws shorter than and radially and axially movable in said slots one edge of each of which contacts with the cam surfaces and the opposite edge of which is shaped to form an eccentric cam surface for gripping a tool shank by a rocking movement, and an abutment'at the inner end of the central aperture for limitin relative axial movement of the chuck bo y and a tool shank and the jaws clamping the lat-T ter to prevent the tapered shank under op-' erating pressure from wedgingthe jaws against t e cam surfaces with force sufiicient to prevent hand operation "of said member.

10. In a rotating chuck for ta ered tool shanks, the oombination'with a c uck. body having radial slots opening into a central aperture, of a spring pressed rotary and axially movable member surrounding the chuck body and operable by hand against the action of its spring while the chuck is rotating and having cam surfaces for opaxial movement of the chuck body and a tool shank and the jaws clampi'n the latter and the member operating the aws to prevent the tapered shank under operating pressure from wedging the jaws against the cam surfaces with force sufiicient to prevent hand operation of said member.

11. In a chuck, the combination with a body having a radial slot opening into a central aperture, of a jaw mounted to rock within the slot, means for moving the jaw inwardly through the slot into contact with the tool shank in the aperture the inner edge of the jaw being provided with an eccentric cam surface adapted to engage a tool shank in the aperture and to be rocked within the slot by the tool shank to firmly grip said shank, and means for rocking the jaw in a reverse direction to return it to its normal position after a tool shank has been released. 12. In a chuck, the combination with a body having a radial slot opening into a central aperture, of a jaw mounted to rock position after a tool shank has been re- Within the slot, means for moving the jaw leased. inwardly through the slot into contact with In testimony whereof, I have signed my the tool shank in the aperture the inner edge name to this specification inthe presence of 5 of the jw beilg prgvided with an eccentric two subscribing witnesses.

cam sur ace a apte to enga e a tool shank in the aperture and to be roc ked Within the VERNER WAHLSTROM' slot by the tool shank to firmly grip said Witnessesr shank, and a spring for rocking the jaw in a SYDNEY I. Pnnsoo'rr,

10 reverse direction to return it to its normal ELIZABETH L. RUSSELL. 

